1. Field of the Invention
The present invention relates to a manifold valve in which directional control valves are provided on manifold bases.
2. Description of the Related Art
A manifold valve, in which directional control valves are installed on manifold bases each having a supply flow passage and exhaust flow passages for a pressurized fluid in order to collectively supply and exhaust the pressurized fluid to and from a plurality of directional control valves, has been already known, for which no special exemplary illustration may be necessary. In such a manifold valve, a plurality of directional control valves are arranged in a linking manner, whereby the pressurized fluid can be collectively supplied and exhausted to and from each of the directional control valves.
In the aforementioned manifold valve, two output ports, which are provided in each of the directional control valves, communicate individually with two output openings provided and opened on a frontal surface of the manifold base in a vertical direction through output flow passages provided in each of the manifold bases, and tube fittings for respectively connecting tubes are attached to the two output openings.
However, the aforementioned tube fittings are restricted in diameter in accordance with the diameters of the tubes inserted thereinto; and therefore, the tubes and tube fittings generally are required to have fixed predetermined diameters. Therefore, when two of such tube fittings are attached on the frontal surface of the manifold base in a vertical direction, a problem arises in that the manifold base necessarily has a large height, the entire manifold valve has a large occupying space, and it is impossible to make the apparatus compact.
A known type of manifold valve is shown in FIG. 12. The manifold valve 2 comprises a manifold base 4 and a directional control valve 6, wherein the directional control valve 6 is constituted by a main valve 8 and a pilot valve portion 9 including a solenoid. Therefore, since the directional control valve 6 is secured on the manifold base 4, it is inevitable that the height H1 and length L1 of the manifold valve 2 are extremely large because the pilot valve portion 9 protrudes on the side surface thereof.
This problem can be solved by allowing the two output openings to be provided and opened in a direction in which the manifold bases are linked together, namely in a horizontal direction. However, when the output openings are provided in such a horizontal direction, a difficult problem arises in that the manifold base has a large width, and the occupying space increases in the horizontal direction, also making the apparatus undesirably large in size.
On the other hand, when a directional control valve of an electromagnetic valve driven type is provided, in which a valve body is driven by a solenoid, the solenoid can be attached at a position above a lower surface of the main valve body.